1. Field of the Invention
The invention generally relates to a signal-processing arrangement and method in which a sampling operation is carried out. Such a signal-processing arrangement may be, for example, a video data acquisition and conversion chain incorporating an analog-to-digital (A/D) converter. Such a signal-processing arrangement may also be, for example, an A/D converter as such.
2. Description of the Related Art
The article "Fully Bipolar, 120-Msample/s 10-b Track-and-Hold Circuit" by P. Vorenkamp and J. P. M. Verdaasdonk, IEEE JSSC, Vol. 27, No. 7, July 1992, pp. 988-992 describes a prior-art video data acquisition and conversion chain. At the input of the chain an analog video signal is applied. The analog video signal is filtered and fed into a track-and-hold (T/H) circuit which carries out a sampling operation. The sampled analog video signal is fed into a data conversion and processing module consisting of an A/D converter, a digital signal processor (DSP), and a digital-to-analog (D/A) converter. The cited article mentions that the T/H circuit, which is used as a presampler in front of the A/D converter, improves the high-frequency performance of the A/D converter.
U.S. Pat. No. 4,831,379, issued May 16, 1989(attorney's docket PHA 1,137) assigned to a related assignee, describes a prior-art A/D converter which comprises an array of 64 input amplifiers. Assuming that i is an integer ranging from 0 to 63, each amplifier Ai amplifies the difference between an analog input voltage and a corresponding reference voltage VRi to produce an amplified output voltage VAi. The amplified output voltages VA0-VA63 are processed in a folding array and an interpolation circuit to produce complementary signals VD0/VDN0 . . . VD31/VDN31 from which signals an output code.